Place the cleaned and chopped strawberries in a small saucepan with the sugar and lemon juice. Cook quickly, then set aside. Puree the mixture.

Prepare the crust: In a bowl, combine the butter (cut into pieces) and sugar, and mix together. In a separate bowl, beat the egg with a fork, then add it to the dough. Add the flour and vanilla extract. Work the dough quickly and chill in the refrigerator for about 1 hour.

Meanwhile, make the frangipane. In a food processor, blend all the ingredients until you have a creamy, sticky mixture. Transfer to a piping bag and set aside.

Take the crust from the fridge and roll it out in a tart pan. Spread a layer of the cooked and pureed strawberries over the crust, then pipe the frangipane on top. Bake at 350°F (180°C) for about 35 minutes, until the frangipane is nicely golden.

Let the tart cool. Meanwhile, soak the gelatin sheets in cold water. Heat the cream in a small saucepan with a few tablespoons of the cooked and pureed strawberries. Add the squeezed gelatin, stir to dissolve, and pour over the tart. Refrigerate for a few hours.

Remove from the fridge and decorate as you like with fresh strawberries and blueberries. You can also add small crust flowers made from leftover dough and dusted with powdered sugar.